[llvm-readelf] Allow prefix flags for -p and -x

[rupprecht]

Summary

This allows syntax like llvm-readelf -p.data1 -x.data2.

[jhenderson]

LGTM, with two small comment nits.

llvm/test/tools/llvm-readobj/hexdump.test

7

-j -> -x?

llvm/test/tools/llvm-readobj/string-dump.test

1

Might be worth adding a comment to say that you're testing the various different ways of specifying the switches.

[rupprecht]

• Update test comments

llvm/test/tools/llvm-readobj/hexdump.test

7

Yep, I shamelessly copy/paste and forget to update bits like this :)

llvm/test/tools/llvm-readobj/hexdump.test

 // Check dumping of the hexadecimal bytes of a section.
 RUN: llvm-readobj -x .text %p/../../Object/Inputs/hello-world.elf-x86-64 | FileCheck %s
 
 CHECK: Hex dump of section '.text':
 CHECK-NEXT: {{^}}0x00400460
+
+// Test that the -j alias can be used flexibly. Create a baseline and ensure
+// all other combinations are identical.
+RUN: llvm-readelf --file-header --hex-dump=.text \
+RUN:   %p/../../Object/Inputs/hello-world.elf-x86-64 > %t.hexdump.out
+RUN: llvm-readelf -h --hex-dump .text \
+RUN:   %p/../../Object/Inputs/hello-world.elf-x86-64 > %t.hexdump.1
+RUN: llvm-readelf -h -x .text \
+RUN:   %p/../../Object/Inputs/hello-world.elf-x86-64 > %t.hexdump.2
+RUN: llvm-readelf -h -x=.text \
+RUN:   %p/../../Object/Inputs/hello-world.elf-x86-64 > %t.hexdump.3
+RUN: llvm-readelf -h -x.text \
+RUN:   %p/../../Object/Inputs/hello-world.elf-x86-64 > %t.hexdump.4
+RUN: llvm-readelf -hx .text \
+RUN:   %p/../../Object/Inputs/hello-world.elf-x86-64 > %t.hexdump.5
+RUN: llvm-readelf -hx=.text \
+RUN:   %p/../../Object/Inputs/hello-world.elf-x86-64 > %t.hexdump.6
+RUN: llvm-readelf -hx.text \
+RUN:   %p/../../Object/Inputs/hello-world.elf-x86-64 > %t.hexdump.7
+
+RUN: cmp %t.hexdump.out %t.hexdump.1
+RUN: cmp %t.hexdump.out %t.hexdump.2
+RUN: cmp %t.hexdump.out %t.hexdump.3
+RUN: cmp %t.hexdump.out %t.hexdump.4
+RUN: cmp %t.hexdump.out %t.hexdump.5
+RUN: cmp %t.hexdump.out %t.hexdump.6
+RUN: cmp %t.hexdump.out %t.hexdump.7

llvm/test/tools/llvm-readobj/string-dump.test

 # Check the dumping of a section as strings.
 # RUN: yaml2obj %s > %t
 
-# RUN: llvm-readobj --string-dump=.strings --string-dump=.not_null_terminated %t | FileCheck %s
-# RUN: llvm-readobj -p=.strings -p=.not_null_terminated %t | FileCheck %s
-# RUN: llvm-readobj --string-dump=1 --string-dump=2 %t | FileCheck %s
-
-# RUN: llvm-readelf --string-dump=.strings --string-dump=.not_null_terminated %t | FileCheck %s
-# RUN: llvm-readelf -p=.strings -p=.not_null_terminated %t | FileCheck %s
-# RUN: llvm-readelf --string-dump=1 --string-dump=2 %t | FileCheck %s
+# RUN: llvm-readobj --string-dump=.strings \
+# RUN:   --string-dump=.not_null_terminated %t > %t.readobj.out
+# RUN: FileCheck %s --input-file=%t.readobj.out
+
+# RUN: llvm-readobj -p=.strings -p=.not_null_terminated %t > %t.readobj.1
+# RUN: llvm-readobj -p.strings -p.not_null_terminated %t > %t.readobj.2
+# RUN: llvm-readobj --string-dump=1 --string-dump=2 %t > %t.readobj.3
+# RUN: llvm-readobj -p1 -p2 %t > %t.readobj.4
+# RUN: llvm-readobj -p=1 -p=2 %t > %t.readobj.5
+
+# RUN: cmp %t.readobj.out %t.readobj.1
+# RUN: cmp %t.readobj.out %t.readobj.2
+# RUN: cmp %t.readobj.out %t.readobj.3
+# RUN: cmp %t.readobj.out %t.readobj.4
+# RUN: cmp %t.readobj.out %t.readobj.5
+
+# Run readelf tests with --file-header as well so we can group -p with
+# something.
+# RUN: llvm-readelf --file-header --string-dump=.strings \
+# RUN:   --string-dump=.not_null_terminated %t > %t.readelf.out
+# RUN: FileCheck %s --input-file=%t.readelf.out
+
+# RUN: llvm-readelf -h -p=.strings -p=.not_null_terminated %t > %t.readelf.1
+# RUN: llvm-readelf -p.strings -hp.not_null_terminated %t > %t.readelf.2
+# RUN: llvm-readelf -h --string-dump=1 --string-dump=2 %t > %t.readelf.3
+# RUN: llvm-readelf -hp1 -p2 %t > %t.readelf.4
+# RUN: llvm-readelf -hp 1 -p.not_null_terminated %t > %t.readelf.5
+# RUN: llvm-readelf -p=1 -hp=2 %t > %t.readelf.6
+
+# RUN: cmp %t.readelf.out %t.readelf.1
+# RUN: cmp %t.readelf.out %t.readelf.2
+# RUN: cmp %t.readelf.out %t.readelf.3
+# RUN: cmp %t.readelf.out %t.readelf.4
+# RUN: cmp %t.readelf.out %t.readelf.5
+# RUN: cmp %t.readelf.out %t.readelf.6
 
 # CHECK:      String dump of section '.strings':
 # CHECK-NEXT: [ 0] here
 # CHECK-NEXT: [ 5] are
 # CHECK-NEXT: [ 9] some
 # CHECK-NEXT: [ e] strings
 # CHECK-NEXT: String dump of section '.not_null_terminated':
 # CHECK-NEXT: [ 0] no

llvm/tools/llvm-readobj/llvm-readobj.cpp

cl::alias ProgramHeadersShort("l", cl::desc("Alias for --program-headers"),
                                 cl::aliasopt(ProgramHeaders), cl::NotHidden);
   cl::alias SegmentsAlias("segments", cl::desc("Alias for --program-headers"),
                           cl::aliasopt(ProgramHeaders));
 
   // -string-dump, -p
   cl::list<std::string> StringDump("string-dump", cl::desc("<number|name>"),
                                    cl::ZeroOrMore);
   cl::alias StringDumpShort("p", cl::desc("Alias for --string-dump"),
-                            cl::aliasopt(StringDump));
+                            cl::aliasopt(StringDump), cl::Prefix);
 
   // -hex-dump, -x
   cl::list<std::string> HexDump("hex-dump", cl::desc("<number|name>"),
                                 cl::ZeroOrMore);
   cl::alias HexDumpShort("x", cl::desc("Alias for --hex-dump"),
-                         cl::aliasopt(HexDump));
+                         cl::aliasopt(HexDump), cl::Prefix);
 
   // -demangle, -C
   cl::opt<bool> Demangle("demangle",
                          cl::desc("Demangle symbol names in output"));
   cl::alias DemangleShort("C", cl::desc("Alias for --demangle"),
                           cl::aliasopt(Demangle), cl::NotHidden);
 
   // -hash-table